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Group Meeting. November 26 th , 2012 Derek Hernandez. Motivation. Method to control topography and chemistry in 3D Derive a better understanding of how these cues can be used to improve migration and alignment in 3D. Chemical Matrix composition Growth factors. Cell behavior Migration
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Group Meeting November 26th, 2012 Derek Hernandez
Motivation • Method to control topography and chemistry in 3D • Derive a better understanding of how these cues can be used to improve migration and alignment in 3D • Chemical • Matrix composition • Growth factors • Cell behavior • Migration • Adhesion • Differentiation • Proliferation • Contact • Matrix stiffness • Topography • Compliance • Cellular • Junctions • Paracrine signals Lust, JR. University of Rochester, Institute of Optics. Scale bar = 2 µm
Protocol to immobilize cues on protein structures • 1) Fabricate protein structure • Concentrated protein solution • Photosensitizer • High laser intensity • 2) Immobilize BP-biotin • 2 mg/mL BP-biotin solution • Reduced laser intensity Remove fabrication solution Protein structure Benzophenone-biotin Neutravidin Biotinylated peptide with PEG linker 3) Bind peptide using neutravidin-biotin chemistry Remove BP-biotin solution
Effect of laser power Functionalization Scans 2 4 6 Scan conditions 2 mg/mL BP-Biotin 10% DMSO 40 mW, 40X objective 0.1 Hz (~30 µm/s)
Future work • Focus on limited power range (0-70 mW) • Test the effects of: • BP-biotin concentration • BSA structure density
Effect of immobilization on surface topography • Average roughness of BSA structure is ~100 nm
Laser-induced shrinking Trying to quantify modulus changes
Improving cell interaction with RGD peptide immobilization Cells adhere strongly to and flatten on RGD-functionalized BSA structures Cells have negative adhesion preferences for unmodified BSA structures
Conclusion • Cell interaction with structure confined mostly to RGD-functionalized regions Future Work: • Establish a quantifiable metric for cell interaction • Use UV excitation to determine target RGD concentration range • Use professionally manufactured biotin-RGD-FITC